Air movement visualization device

ABSTRACT

A portable device for checking wind direction discharges a visible, and optionally scented, vapor stream into the atmosphere in a well-defined reference direction. In some embodiments, the device includes a power source, a vessel having an internal plenum chamber storing a volume of air, a reservoir containing a vaporizable agent, a vaporizing element associated with the vaporizable agent, and a pressure switch. The vessel is deformable to generate an airflow that operates the pressure switch to temporarily connect the power source to the vaporizing element, thereby energizing the vaporizing element to generate vapor. The airflow also carries the vapor into the atmosphere as a visible vapor stream flowing in the reference direction. The reservoir and vaporizing element may be carried in a cartridge removably mounted on the device. Other embodiments operate similarly, but use alternative means for generating gaseous flow to operate the switch and/or carry vapor into the atmosphere.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority benefit of U.S. Provisional Application No. 62/177,796 filed Mar. 25, 2015, the entirety of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to devices that allow a user to visually determine wind currents, drafts, and other types of airflow. Such devices are used, for example, by hunters, golf players, sailors, and HVAC technicians.

BACKGROUND OF THE INVENTION

Devices for visualizing wind currents and other types of airflow are known. In a common arrangement, a resiliently deformable bottle carries a fine powder material, and the user squeezes the bottle to discharge a puff of air including the visible powder material into the atmosphere. The powdered stream of air may be viewed by the user as it is acted upon by wind currents or other localized airflow, thereby providing the user with a visual indication of the direction and strength of such airflow. Examples of powder discharge visualization devices are described in U.S. Pat. No. 5,186,118 (Stinson); U.S. Pat. No. 7,765,863 (Woolsey); and U.S. Pat. No. 8,424,379 (Bibby). A disadvantage of this type of device is that the powder is susceptible to clumping caused by humid atmospheric conditions, and this may render the device unusable. Powder discharge devices are also messy to reload.

Electronic wind gauges are also known wherein a liquid is vaporized by energizing a heating element. Examples of this type of wind gauge are disclosed in U.S. Pat. No. 2,311,199 (Åstradsson) and U.S. Pat. No. 4,326,119 (Swiatosz). Known electronic wind gauges are structurally complex and do not provide an organized stream of air for carrying the vapor into the atmosphere as a well-defined line of vapor indicating a reference direction. Unintended discharge may also be a problem if the electronic device is accidentally turned on when a user is reaching for other equipment, such as a gun or ammunition.

What is needed is a reliable, compact, easily portable wind tracking device that discharges a well-defined line of visible vapor and is not susceptible to accidental discharge.

SUMMARY OF THE INVENTION

The present invention provides a compact portable device for checking wind direction and strength by discharging a visible vapor stream into the atmosphere. The vapor stream is discharged in a well-defined reference direction, and the effects of local wind or air currents on the vapor stream may be visually observed by a user to qualitatively judge direction and strength of the wind or air currents. The vapor stream may carry a scent, for example a scent that attracts animals and/or disguises human scent.

In some embodiments, the device generally comprises a power source, a vessel including an internal plenum chamber for storing a volume of air, a reservoir containing a vaporizable agent, a vaporizing element associated with the vaporizable agent, and a pressure switch activated by airflow. The vessel is deformable to generate a flow of air, and the pressure switch is arranged in the flow of air and is operated by the flow of air to selectively connect the power source to the vaporizing element, thereby energizing the vaporizing element to vaporize at least a portion of the vaporizable agent. The flow of air also carries the vapor into the atmosphere as a visible vapor stream flowing in a reference direction. The vaporizing agent may be a glycol-based fluid, and the vaporizing element may be a heating element of piezoelectric element arranged in association with the vaporizable agent.

The reservoir and the vaporizing element may be carried in a cartridge that is removably mounted on the device. The reservoir may have a vapor discharge passage defining the reference direction of the vapor stream. The device may further comprise a removable cap for preventing airflow from the plenum chamber of the vessel to the atmosphere when the device is not in use, wherein the cap includes an internal stopper arranged to seal the vapor discharge passage. The vessel may be embodied as a hollow bladder made of resiliently deformable material, or as a bellows or piston and cylinder.

Other embodiments operate in a similar manner, but comprise various alternative means for generating a flow of air or other gas to operate the switch and/or carry generated vapor into the atmosphere. For example, alternative embodiments are disclosed that use a fan, a user's exhalation, and a container of pressurized gas, respectively, to generate gaseous flow.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which:

FIG. 1 is a perspective view showing an air movement visualization apparatus formed in accordance with a first embodiment of the present invention being used by hunter;

FIG. 2 is a perspective view of the air movement visualization apparatus shown in FIG. 1;

FIG. 3 is an exploded perspective view of the air movement visualization apparatus shown in FIG. 1;

FIG. 4 is a perspective view of a battery housing and vapor cartridge subassembly of the apparatus shown in FIG. 1;

FIG. 5 is an exploded perspective view of the subassembly shown in FIG. 4;

FIG. 6 is a cross-sectional view of the subassembly taken generally along the line 6-6 in FIG. 4;

FIG. 7 is an enlarged cross-sectional view of a coupling region of the subassembly shown in FIGS. 4-6;

FIG. 7A is an enlarged cross-sectional view showing an alternative vaporizing element of the apparatus;

FIG. 8 is a cross-sectional view taken generally along the line 8-8 in FIG. 2 illustrating operation of the apparatus of the first embodiment;

FIG. 9 is a perspective view of an air movement visualization apparatus formed in accordance with a second embodiment of the present invention;

FIG. 10 is an exploded perspective view of the air movement visualization apparatus shown in FIG. 9;

FIG. 11 is a cross-sectional view taken generally along the line 11-11 in FIG. 9;

FIG. 12 is a perspective view of an air movement visualization apparatus formed in accordance with a third embodiment of the present invention;

FIG. 13 is a cross-sectional view taken generally along the line 13-13 in FIG. 12;

FIG. 14 is an enlarged cross-sectional view showing a one-way check valve of the apparatus shown in FIGS. 12 and 13;

FIG. 15 is a perspective view of an air movement visualization apparatus formed in accordance with a fourth embodiment of the present invention;

FIG. 16 is a cross-sectional view taken generally along the line 16-16 in FIG. 15;

FIG. 17 is a perspective view of an air movement visualization apparatus according to a variation of the fourth embodiment of the present invention;

FIG. 18 is a cross-sectional view taken generally along the line 18-18 in FIG. 17;

FIG. 19 is a perspective view of an air movement visualization apparatus formed in accordance with a fifth embodiment of the present invention;

FIG. 20 is a cross-sectional view taken generally along the line 20-20 in FIG. 19;

FIG. 21 is a perspective view of an air movement visualization apparatus formed in accordance with a sixth embodiment of the present invention; and

FIG. 22 is a cross-sectional view taken generally along the line 22-22 in FIG. 21.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 through 8 show an apparatus 10 formed in accordance with a first embodiment of the present invention. Apparatus 10 is a portable hand-held device operable by a user to visualize air movement. Apparatus 10 has utility for hunters, golf players, sailors, military personnel, and others seeking to determine wind direction and strength by visual tracking. Apparatus 10 also has utility for heating and cooling technicians and energy use auditors seeking to visualize flow through air ducts and identify leaky doors, windows, etc. in homes and buildings.

Apparatus 10 generally comprises a power source 12, a vessel 14, a reservoir 16, a vaporizing element 18, and a switch 20. Reservoir 16 contains a vaporizable agent 22, for example propylene glycol, vegetable glycerin, or other organic compound. Vaporizing element 18 is associated with vaporizable agent 22 and may be energized by power source 12 to vaporize vaporizable agent 22. Switch 20 is operable to connect and disconnect vaporizing element 18 to and from power source 12. Vessel 14 includes an internal plenum chamber 24 for storing a volume of air, and is deformable to generate a flow of air. Switch 20 is a pressure-sensitive switch arranged such that the flow of air generated by deforming vessel 14 operates switch 20 to temporarily connect vaporizing element 18 to power source 12. As may be understood, vaporizing element 18 is briefly energized to vaporize some of the vaporizable agent 22, thereby producing visible vapor. The visible vapor is carried by the flow of air into the atmosphere as a thin vapor stream 26 flowing in a reference direction D as it leaves apparatus 10.

Power source 12 may include one or more batteries. The batteries may be rechargeable (e.g. lithium ion, nickel-metal hydride, rechargeable alkaline) or non-rechargeable (e.g. disposable alkaline). As shown in FIGS. 5 and 6, power source 12 may be held within an elongated tubular battery housing 28 having a removable base 30 threadably received at a bottom end of the housing and a threaded mating portion 32 at a top end of the housing. Base 30 may be removed for installing and removing power source 12. Base 30 includes an air inlet passage 34 for allowing air to flow from plenum chamber 24 into battery housing 28. Mating portion 32 includes an air outlet passage 36 for allowing air to flow out of battery housing 28. Thus, battery housing 28 includes an air duct defined by air inlet passage 34, space 35 between power source 12 and an inner wall surface of housing 28, and air outlet passage 36 by which the flow of air generated by compressible vessel 14 is communicated through housing 28 to pressure switch 20 and then out of the housing. While not shown in relation to the first embodiment, battery housing 28 may have one or more side ports at a location near pressure switch 20 through which air may enter the battery housing from plenum chamber 24 for communication with the pressure switch.

Vessel 14 may be embodied as a bulb or bladder made of resiliently deformable material, for example synthetic rubber. Alternatively, vessel 14 may be embodied as a bellows, or as a piston and cylinder mechanism, that is manually compressible to generate a flow of air. As best seen in FIG. 8, battery housing 28 may be partially or fully received within plenum chamber 24 of vessel 14 to keep apparatus 10 small and compact for portability. In the first embodiment, vessel 14 includes an access opening 23 for allowing access to battery housing 28, and a plug 25 received by the access opening for sealing the access opening. Plug 25 is removable from access opening 23 to permit access to housing 28 and to power source 12 contained by the housing. A check valve 27 is provided through which air enters plenum chamber 24 and through which air cannot exit the plenum chamber. Check valve 27 may be incorporated into plug 25, as shown in FIG. 8, or the check valve may be provided through a wall of vessel 14 at another location.

Reservoir 16 contains a supply of vaporizable agent 22. As used herein, the term “vaporize” and alternative forms thereof have a broad meaning encompassing atomize, aerosolize, and similar processes wherein fluid is physically dispersed in air by application of heat and/or vibration. Vaporizable agent 22 may be a liquid or gel held by an absorbent matrix material that surrounds vaporizing element 18.

In FIG. 7, vaporizing element 18 is embodied as a resistive heating element formed of wire. Alternatively, vaporizing element 18 may be embodied as a piezoelectric element as shown in FIG. 7A. When vaporizing element 18 is energized by power source 12, heat or ultrasonic vibrations produced by the vaporizing element act upon vaporizable agent 22 in the vicinity of vaporizing element 18 to generate vapor. Reservoir 16 may be configured to include a vapor discharge passage 38 through which the vapor escapes reservoir 16, wherein the direction of passage 38 defines the reference direction D.

Reservoir 16 and the vaporizing element 18 may be carried in a cartridge 40 removably mounted on apparatus 10. In the first embodiment illustrated by FIGS. 1 through 8, cartridge 40 is removably connected to battery housing 28 by way of a threaded coupler 42. As may be understood, power source 12 and cartridge 40 are independently removable and replaceable, i.e. one may be removed and replaced without removing the other. Upon removal of housing base 30, power source 12 may be removed from housing 28 while cartridge 40 remains connected to housing 28. Cartridge 40 is removable from housing 28 while power source 12 remains in housing 28 by unscrewing cartridge 40 from coupler 42. Apparatus 10 may comprise a rigid tubular receptacle 44 extending from vessel 14, wherein cartridge 40 is slidably received by the receptacle so as to avoid direct frictional contact between cartridge 40 and vessel 14. Receptacle 44 may be metallic, e.g. stainless steel, to reduce friction and facilitate insertion and removal of cartridge 40. Coupler 42 may be fixed to an inner wall surface of receptacle 44. As may be understood, replacement of power source 12 or cartridge 40 is a simple matter that does not require removal of unrelated elements.

Advantageously, threaded coupler 42 may be electrically conductive and may be arranged to electrically connect vaporizing element 18 to pressure switch 20. The electrical connection may be understood by reference to FIGS. 6 and 7. In the depicted embodiment, pressure switch 20 is arranged within battery housing 28 and is connected to the positive and negative terminals of power source 12 by wires 46 and 48, respectively. Switch 20 is also electrically connected to coupler 42 by a positive lead wire 50 contacting a radially inner portion 42A of coupler 42, and by a negative lead wire 52 contacting a radially outer portion 42B of coupler 42. Radially inner and outer portions 42A, 42B are conductive portions electrically insulated from one another by an insulating ring 43. Vaporizing element 18 is connected to pressure switch 20 via coupler 42. When metal cartridge 40 is screwed onto coupler 42, a positive terminal 18A of vaporizing element 18 is electrically connected to inner portion 42A and a negative terminal 18B of vaporizing element 18 is electrically connected to outer portion 42B, thereby forming a circuit including power source 12, pressure switch 20, and vaporizing element 18. An insulating ring 41 is provided in cartridge 40 for electrical insulation between terminals 18A, 18B. Airflow through and/or around battery housing 28 activates pressure switch 20 to temporarily close the switch such that current flows through vaporizing element 18. When the airflow ceases, switch 20 opens to shut off current to vaporizing element 18. Pressure switch 20 may be a commercially available pressure switch or airflow sensor that operates mechanically or has an integrated microprocessor.

FIGS. 9 through 11 depict an air movement visualization apparatus 110 formed in accordance with a second embodiment of the present invention. Apparatus 110 operates in a manner similar to apparatus 10 of the first embodiment, but has some structural differences. For example, coupler 42 is omitted and cartridge 40 is removably connected directly to battery housing 28 by threaded connection. Electrical connection of switch 20 to vaporizing element 18 may be provided through the top portion of housing 28.

In apparatus 110 of the second embodiment, battery housing 28 is fixed to a flanged support bushing 112 received through a top opening in vessel 14 such that the battery housing is suspended within plenum chamber 24. A cover sleeve 114 fits over cartridge 40 and is configured to mate with a removable cap 54. Cap 54 prevents airflow from plenum chamber 24 to the atmosphere when the apparatus is not in use. For example, when cap 54 is tightened to form a seal over reservoir 16, air is trapped within plenum chamber 24 such that vessel 14 cannot be accidentally compressed or squeezed to generate a flow of air that may unintentionally operate switch 20. In the illustrated embodiment, cap 54 includes an internal stopper 56 arranged to seal vapor discharge passage 38. Cap 54 may be provided with a lanyard 58 having a first end coupled to cover sleeve 114 or vessel 14 and a second end coupled to the cap to prevent cap 54 from being lost.

An air movement visualization apparatus 210 formed in accordance with a third embodiment of the present invention is shown in FIGS. 12 through 14. Apparatus 210 operates similar to apparatus 10 of the first embodiment, but incorporates some structural modifications. In apparatus 210, battery housing 28 threadably mates with plug 25, whereby plug 25 acts as a removable base of the housing. Alternatively, plug 25 may be press fitted or snap fitted into the open bottom end of battery housing 28. Access to power source 12 may be gained by unscrewing or otherwise removing plug 25 from battery housing 28 and the bottom of vessel 14. Instead of an air duct extending axially through the length of battery housing 28, a side port 212 is provided through housing 28 such that airflow enters housing 28 near switch 20 to activate the switch. Switch 20 is depicted as a mechanical pressure switch. Check valve 27 is arranged through a side wall of vessel 14, independent of plug 25.

FIGS. 15 and 16 illustrate an air movement visualization apparatus 310 formed in accordance with a fourth embodiment of the present invention. Apparatus 310 operates in a manner generally similar to the first through third embodiments described above, however it differs from the previous embodiments in that apparatus 310 comprises a small electric fan 312 to generate a flow of air. Fan 312 may be mounted at a base of apparatus shell 314 to provide airflow through battery housing 28, switch 20, and cartridge 40. Fan 312 may be mounted to the base of shell 314 by mating threads 315 so that fan 312 can be unscrewed from shell 314 to permit replacement of power source 12. Apparatus 310 has a manually operated switch 316 for selectively connecting fan 312 to power source 12 to turn the fan on and off. The airflow generated by fan 312 may be used to activate pressure switch 20 to energize vaporizing element 18. Alternatively, manually operated fan switch 316 may be arranged such that it selectively connects both fan 312 and vaporizing element 18 to power source 12, whereby pressure switch 20 may be omitted from apparatus 310. As will be appreciated, the airflow generated by fan 312 carries vapor generated in reservoir 16 through vapor discharge passage 38 and into the atmosphere as a vapor stream flowing in reference direction D. Fan switch 316 may be a momentary switch that shuts off power to fan 312 automatically after a brief predetermined period of time sufficient to cause a stream of vapor to be discharged. Alternatively, fan switch 316 may be an on-off locking switch that remains switched on until the user switches it off.

In a variation of the fourth embodiment depicted in FIGS. 17 and 18, power source 12 may be arranged out of alignment with fan 312 and vapor discharge passage 38. This variation reduces the overall height of apparatus 310. This variation also allows for replacement of power source 12 without removal of fan 312. More specifically, a hinged or otherwise movable cover 318 may be provided on shell 314 to permit direct access to power source 12 without removing fan 312.

In the fourth embodiment, as in the first through third embodiments, the reservoir 16 and the vaporizing element 18 are carried in a cartridge 40 removably mounted on the apparatus. As shown in FIGS. 16 and 18, cartridge 40 may be threadably connected to battery housing 28. Power source 12 is removable from housing 28 while cartridge 40 remains connected to housing 28 by removing fan 312 in FIGS. 15 and 16, or by opening cover 318 in the variation of FIGS. 17 and 18. Cartridge 40 can be unscrewed from housing 28 while power source 12 remains in battery housing 28. Like previous embodiments, cap 54 includes internal stopper 56 arranged to seal vapor discharge passage 38. In the variation of FIGS. 17 and 18, internal stopper 56 may be arranged on the underside of cover 318.

FIGS. 19 and 20 show an air movement visualization apparatus 410 formed in accordance with a fifth embodiment of the present invention. Apparatus 410 operates by a user blowing into a mouthpiece 412 at one end of the apparatus. Mouthpiece 412 may be removable, for example by threaded or slidable mounting, from apparatus shell 414. A flexible mouthpiece attachment 416 may be provided having remote mouthpiece 418 communicating with original mouthpiece 412 or with an inlet port 422 of shell 414 through a flexible tube 420. Tube 420 may have an end fitting 424 for quick connection to original mouthpiece 412 or directly to inlet port 422. Flexible mouthpiece attachment 416 allows apparatus 410 to be freely orientated and viewed by the user while blowing into mouthpiece 412 so that the vapor stream may be viewed. Power source 12 is preferably located out of alignment with inlet port 422 and vapor discharge passage 38 to provide a clear path and facilitate actuation of pressure switch 20 by the user. Switch 20 may be connected to vaporizing element 18 by coupler 42 as described in connection with the first embodiment. Cartridge 40 may be threadably connected to coupler 42. A separate door 426 may be provided in shell 414 to allow access to power source 12.

An air movement visualization apparatus 510 formed in accordance with a sixth embodiment of the present invention is illustrated in FIGS. 21 and 22. Apparatus 510 includes a rigid container 512 holding pressurized gas, such as air. Container 512 includes a release valve 513 operable to release a flow of gas from the container. For example, in the embodiment shown, release valve 513 is opened by pressing container 512 in a downward direction as viewed in FIG. 22. An actuating member 516 may be provided at an end of container 512 opposite release valve 513, wherein the actuating member 516 may be pressed by a user to apply force to operate release valve 513. For example, actuating member 516 may be pivotally hinged to an outer shell 514 of apparatus 510.

Apparatus 510 may comprise a gas duct 518 arranged to communicate a flow of gas released through valve 513 to pressure switch 20, thereby activating the pressure switch to temporarily connect vaporizing element 18 to power source 12. As in the previous embodiments, the flow of gas carries vapor into the atmosphere as a vapor stream flowing in reference direction D.

When rigid container 512 loses its charge of pressurized gas, it may be replaced with a charged container by pivoting actuating member 516 back to allow container 512 to be withdrawn from a compartment 515 of apparatus shell 514 and the new container to be inserted into the compartment. A separate door (not shown) may be provided in shell 514 to allow access to power source 12.

As an optional feature applicable to all the embodiments described herein, vaporizable agent 22 may be scented. For example, vaporizable agent 22 may contain scents for luring deer and other animals, obscuring human scent, and/or repelling insects. Vaporizable agent 22 may also contain pleasing scents, such as scents produced by essential oils.

As another optional feature applicable to all embodiments, a safety shut-off switch may be provided to ensure that power source 12 is not drained down unnecessarily should pressure switch 20 or fan switch 316 fails to automatically shut off (where fan switch 316 is momentary), or where the user forgets to turn fan switch 316 off (where fan switch 316 is a locking on-off switch).

As a further optional feature applicable to all embodiments, a fuel gauge may be provided to indicate charge remaining in power source 12 or to indicate when remaining charge falls below a threshold level. For example, a blinking LED may be used to signal to the user that the charge remaining in power source 12 has dropped below a threshold level and the power source 12 should be recharged or replaced.

While the invention has been described in connection with exemplary embodiments, the detailed description is not intended to limit the scope of the invention to the particular forms set forth. The invention is intended to cover such alternatives, modifications and equivalents of the described embodiment as may be included within the scope of the invention. 

What is claimed is:
 1. An apparatus comprising: a power source; a vessel including an internal plenum chamber for storing a volume of air, the vessel being deformable to generate a flow of air; a reservoir containing a vaporizable agent; a vaporizing element associated with the vaporizable agent; and a switch arranged in the flow of air, the switch being operable to selectively connect the power source to the vaporizing element, thereby energizing the vaporizing element to vaporize at least a portion of the vaporizable agent; wherein the flow of air operates the switch such that vapor is produced; wherein the flow of air carries the vapor into the atmosphere as a visible vapor stream flowing in a reference direction.
 2. The apparatus according to claim 1, wherein the reservoir and the vaporizing element are carried in a cartridge removably mounted on the apparatus.
 3. The apparatus according to claim 2, further comprising a housing containing the power source, wherein the cartridge is removably connected to the housing.
 4. The apparatus according to claim 3, wherein the power source is removable from the housing while the cartridge remains connected to the housing.
 5. The apparatus according to claim 4, wherein the cartridge is removable from the housing while the power source remains in the housing.
 6. The apparatus according to claim 3, wherein the cartridge is removably connected directly to the housing.
 7. The apparatus according to claim 3, wherein the cartridge is removably connected to the housing by way of a threaded coupler.
 8. The apparatus according to claim 7, wherein the threaded coupler is electrically conductive and is arranged to electrically connect the vaporizing element to the switch.
 9. The apparatus according to claim 3, wherein the housing is at least partially received within the plenum chamber.
 10. The apparatus according to claim 9, wherein the vessel includes an access opening, and the apparatus further comprises a plug received by the access opening for sealing the access opening, wherein the plug is removable from the access opening to permit access to the housing and to the power source contained by the housing.
 11. The apparatus according to claim 10, further comprising a check valve through which air enters the plenum chamber and through which air cannot exit the plenum chamber, wherein the plug includes the check valve.
 12. The apparatus according to claim 3, wherein the housing includes an air duct by which the flow of air is communicated to the switch.
 13. The apparatus according to claim 2, further comprising a rigid tubular receptacle extending from the vessel, wherein the cartridge is slidably received by the receptacle.
 14. The apparatus according to claim 1, wherein the vaporizing element includes a heating element.
 15. The apparatus according to claim 1, wherein the vaporizing element includes a piezoelectric element.
 16. The apparatus according to claim 1, wherein the reservoir includes a vapor discharge passage defining the reference direction.
 17. The apparatus according to claim 16, further comprising a removable cap for preventing airflow from the plenum chamber to the atmosphere when the apparatus is not in use, wherein the cap includes an internal stopper arranged to seal the vapor discharge passage.
 18. The apparatus according to claim 1, wherein the vessel includes a hollow bladder made of resiliently deformable material.
 19. The apparatus according to claim 1, wherein the vessel includes a bellows.
 20. The apparatus according to claim 1, wherein the vessel includes a piston and cylinder.
 21. The apparatus according to claim 1, further comprising a check valve through which air enters the plenum chamber and through which air cannot exit the plenum chamber.
 22. The apparatus according to claim 1, further comprising a removable cap for preventing an unintended flow of air from the plenum chamber to the atmosphere when the apparatus is not in use.
 23. The apparatus according to claim 1, wherein the vaporizable agent is scented.
 24. An apparatus comprising: a power source; a fan; a reservoir containing a vaporizable agent; a vaporizing element associated with the vaporizable agent; and at least one switch operable to selectively connect the power source to the fan and the vaporizing element, thereby activating the fan to generate a flow of air and energizing the vaporizing element to vaporize at least a portion of the vaporizable agent to produce vapor; wherein the flow of air carries the vapor into the atmosphere as a visible vapor stream flowing in a reference direction, wherein the at least one switch includes a fan switch and a vaporizing element switch, wherein the fan switch is operated by a user to connect the power source to the fan, and the vaporizing element switch is arranged in the flow of air and is operated by the flow of air.
 25. The apparatus according to claim 24, wherein the fan switch is a momentary switch.
 26. The apparatus according to claim 24, wherein the fan switch is an on-off locking switch.
 27. The apparatus according to claim 24, wherein the reservoir and the vaporizing element are carried in a cartridge removably mounted on the apparatus.
 28. The apparatus according to claim 27, further comprising a housing containing the power source, wherein the cartridge is removably connected to the housing.
 29. The apparatus according to claim 28, wherein the power source is removable from the housing while the cartridge remains connected to the housing.
 30. The apparatus according to claim 29, wherein the cartridge is removable from the housing while the power source remains in the housing.
 31. The apparatus according to claim 29, wherein the fan is removably mounted to the housing at a base of the housing, and the power source is removable from the housing when the fan is removed.
 32. The apparatus according to claim 24, wherein the reservoir includes a vapor discharge passage defining the reference direction, and the fan is aligned with the vapor discharge passage.
 33. The apparatus according to claim 32, wherein the power source is aligned with the fan and the vapor discharge passage.
 34. The apparatus according to claim 32, wherein the power source is not aligned with the fan and the vapor discharge passage.
 35. The apparatus according to claim 24, wherein the vaporizable agent is scented.
 36. An apparatus comprising: a power source; a fan; a reservoir containing a vaporizable agent; a vaporizing element associated with the vaporizable agent; and at least one switch operable to selectively connect the power source to the fan and the vaporizing element, thereby activating the fan to generate a flow of air and energizing the vaporizing element to vaporize at least a portion of the vaporizable agent to produce vapor; wherein the flow of air carries the vapor into the atmosphere as a visible vapor stream flowing in a reference direction, further comprising a removable cap, wherein the cap includes an internal stopper arranged to seal the vapor discharge passage.
 37. An apparatus comprising: a power source; a housing including a fluid passageway; a mouthpiece mounted on the housing, the mouthpiece including an inlet conduit communicating with the fluid passageway, whereby a user generates a fluid flow through the inlet conduit and the fluid passageway by blowing into the mouthpiece; a reservoir containing a vaporizable agent; a vaporizing element associated with the vaporizable agent; and a switch arranged in the fluid flow, the switch being operable to selectively connect the power source to the vaporizing element, thereby energizing the vaporizing element to vaporize at least a portion of the vaporizable agent; wherein the fluid flow operates the switch such that vapor is produced; wherein the fluid flow carries the vapor into the atmosphere as a visible vapor stream flowing in a reference direction.
 38. The apparatus according to claim 37, wherein the mouthpiece is removably mounted on the housing.
 39. The apparatus according to claim 37, wherein the mouthpiece includes a length of flexible tubing.
 40. The apparatus according to claim 37, wherein the vaporizable agent is scented.
 41. An apparatus comprising: a power source; a rigid container holding pressurized gas, the container including a release valve operable to release a flow of gas from the container; a reservoir containing a vaporizable agent; a vaporizing element associated with the vaporizable agent; and a switch arranged in the flow of gas, the switch being operable to selectively connect the power source to the vaporizing element, thereby energizing the vaporizing element to vaporize at least a portion of the vaporizable agent; wherein the flow of gas operates the switch such that vapor is produced; wherein the flow of gas carries the vapor into the atmosphere as a visible vapor stream flowing in a reference direction.
 42. The apparatus according to claim 41, wherein the pressurized gas is air.
 43. The apparatus according to claim 41, wherein a gas duct communicates the flow of gas from the release valve to the switch.
 44. The apparatus according to claim 43, wherein the release valve extends from a first end of the container and is mounted in a manifold connecting the release valve to the gas duct, and the apparatus further comprises an actuating member operable by a user to apply force to a second end of the container opposite the first end to thereby operate the release valve.
 45. The apparatus according to claim 41, wherein the vaporizable agent is scented. 